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Onan JB Thermomagnetic Choke


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  #21  
Old 08-17-2017, 09:14:23 PM
Leon N. Leon N. is offline
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Default Re: Onan JB Thermomagnetic Choke

JoeE let me give you a tip? Get your hands on a copy of your vintage JB parts lists. It contains exploded views illustrating how the individual sub assembly's fit together and identifies individual piece part numbers, etc. I found such a document very informative and helpful when I refurbished my JB which was built to factory spec P.

The Onan document you should have is entitled : Owners Manual and Parts Lists, # 967-320. If you desire, I or others on the Stak can email you a copy post haste. If interested, let me know your email address via a private message. You should also have its companion document entitled: JB/JC Major Overhaul Manual, Onan # 967-500. The later also,contains wiring diagrams that should cover your JB.
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Old 08-17-2017, 09:15:39 PM
nothingbutdarts nothingbutdarts is offline
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Default Re: Onan JB Thermomagnetic Choke

You are correct, no oil pressure shut down switch.

Not a great big deal about the fact you removed the gov. adj, nut, you can get the frequency/RPM set when you put it back together (HOWEVER) when trying to set the RPM you need to have the Magniciter exciter wires disconnected so you don't burn up the gen. section, again not a big deal.
You might consider replacing the seal on the governor shaft as from all the oil in there I guess it is leaking.

You might make a note as to where the governor spring was attached on the gov. arm, there are a few positions the spring can go on.
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  #23  
Old 08-17-2017, 09:19:19 PM
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Billy J Shafer Billy J Shafer is offline
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Default Re: Onan JB Thermomagnetic Choke

Just stick the stud back through the front cover. Back about where you think it was. Use a meter that can read cycles. Then you can readjust the arm.
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  #24  
Old 08-18-2017, 01:05:49 AM
Leon N. Leon N. is offline
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Default Re: Onan JB Thermomagnetic Choke

Your second picture in post #19: Take a scrapper or a stiff brush and scrape or otherwise remove the crude , dirt, etc from around the governor spring arm without disturbing the governor spring attachment point to the cruddy looking governor arm and TAKE another picture of the attachment point for-the-record. That way if and/or when you re assemble you will be able to have a better starting point to set the proper RPM and this frequency from the get go.

BTW! In my opinion it IS a big deal to attempt to remove the Magneciter exciter wires unless you are very familiar with the electrical operation of the Magneciter. I would suggest you leave it alone for now and spend what $25 for a kilowatt/frequency meter.

If you cannot edit your posts and I do not see why you can not, ask Harry or just make another post, no big deal. Right?
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Old 08-18-2017, 07:14:44 AM
Max Thompson Max Thompson is offline
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Default Re: Onan JB Thermomagnetic Choke

In the 2nd picture of your last post (19), under the oil and dirt accumulation you will find the sensitivity adjustment screw that the governor spring is attached to. The other end of the spring attaches to the adjustment screw you removed, the one that protruded through the front fan housing.

You will find assembly and adjustment instructions for the governor system in the service manual.

Looks like a good bath is in order for your Onan. This would make working on it much more pleasant and may allow you to see where the accumulated oil is coming from (likely the governor arm seal).
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  #26  
Old 08-18-2017, 04:25:56 PM
JoeE. JoeE. is offline
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Default Magneciter....

Here are 3 shots of it....
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  #27  
Old 08-18-2017, 05:33:31 PM
Leon N. Leon N. is offline
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Default Re: Magneciter....

I would say your Magneciter looks great! Maybe a little dirty but for now so what. I would not recommend removing any wires with the possible risk of introducing a " bad connection" when you re attach. I would advise trying to take a peak at the two slip rings and tell us either by a picture or in words how they look. Please refer to the Onan manual 967-500 ( which I am about to send you), page 54 where Onan talks about how to check the slip rings and what to look for.
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Old 08-18-2017, 07:02:49 PM
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Default Re: Magneciter....

I see that there are four screwdriver slotted bolts holding the magnesite Iran... Maybe it even hinges out I can't quite tell... Should I take those for loose to look at that ring
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  #29  
Old 08-18-2017, 07:08:43 PM
JoeE. JoeE. is offline
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Default Re: Onan JB Thermomagnetic Choke

There is the rear of the Magneciter, and there are the slip rings... They are a dull bronze color and the brushes are both touching the surface of the slip rings.
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  #30  
Old 08-18-2017, 07:33:47 PM
Leon N. Leon N. is offline
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Default Re: Onan JB Thermomagnetic Choke

From your pictures, I would say the slip rings and brushes are probably fine. Certainly the appearance of your slip rings look very good. I would leave this area alone and concentrate on getting the JB to start and run close to 1800 RPM (60 HZ) .
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